Time delay relay



March 11, 1958 J. H. COULOMBE IETAL 2,826,650

TIME DELAY RELAY Filed May 9, 1955 2 Shets-Sheet 1 \NViNTORS JOHN H.OULOMBE JOHN J. AMBROZAITIS BY ELIOT K. BUCKINGHAM M WM v 'ATTORNEYSFIG. I

March 1958 J. I-I. COULOMBE ET AL 2,82

TIME DELAY RELAY Filed May 9, l955 2 Sheets-Sheet 2 FIG. 4

FIG. 7

FIG. 3

FIG. 6

FIG. 5

FIG. 2

I INVENTOR JOHN H. COULD BE JOHN J. AMBROZAITI B ELIOT K. BUCKINGM Eb.22.01- MJA 1 I ATIJORNEYS United States Patent" TIME DELAY RELAY John H.Coulombe, Middlebury, John Ambrozaitis, Waterbury, and Eliot K.Buckingham, Woodbury, Conn., assignors to ConsolidatedElectronicsindustries Corp., Waterbury, Conn., a corporation of DelawareApplication May 9, 1955, Serial No. 5064876- 15 Claims. (Cl. 200-38)This invent-ionjrelates toa: novel motor-driven timing switch. Morespecifically, this: invention relates to a timing device of the typedescribed wherein two-successive intervals may be timed by the samedevice. The structure of the present. invention utilizes structuralfeatures described in a copending application Serial No. 504,254., filedApril 27, 1955-.

In the prior art there have been various timing switch devices fortiming successive intervals of time. However, these devices have notpermitted. adjustment of the length of the timed periods. The presentinvention is an extension of devices timing successive time intervals inthat it does permit timing adjustments. It is possible to. change thelength of one or both ofv the successive periods-using; the. device; ofthe present invention. Moreover, the present device permits timing tobegin. at any time inresponse to a. signal.

I-nterms-of broadest inclusion, the structure of the present-inventionemploys a. constant speed motor drive on a frame. A. rotatablesystem issupporte-d-. onthe frarneand its parts. are coupled together forsimultaneous rotation. This rotatable system includes first and secondtiming actuators and a limiting arm. Means isprovided for couplingtherotatablesystem to the drive inresponse to: a signal, thus enablingselective timing any time an operator. wishes to. put the. device. intooperation- A spring or other resilient means isprovided between theframe. and the rotatable system. to urge the actuators to rotate in thedirectionopposite that imposedby the drive. Stop means. is positioned tointercept the limiti'ng arm and consequently to limit the rotationimposed by the resilient. means- Eirst and second switchesare supported?on the frame in position to be actuated. by the first and secondactuators, respectively,.in the course of rotation of the system awayfrom. the position in which the. limiting arm engages, the stop.

In the preferred embodiment of the present invention the actuators areplaced side by side and rotate at the same speed on what is effectivelythe same axle. These actuators are preferably cam members, althoughother typesof, actuators, such as radial. arms, could be substituted.Byv one of a variety of means, such as making the axle a. compoundmember, the parts of'which are mutually rotatable, one actuator is ableto be rotatably orangularly adjustedrelative to the other. Thepositioning of the actuators effects an adjustment in at least one ofthe successive timed periods; perferably the later periodi The earlierperiod may then be adjusted by rotatableadjustmentofthe stop in order tochange the zero position 'of therotatable system. Inthe preferredformzof; the invention the stop=is mounted on arotatable member: whichhas. the; same. axis: of rotation as the limiting arm;

In the preferredxmbodirnent during-timing, the rotatable, system is,driven away. fromits zeroposition. The length of, the. first. timedperiod is. determinedby the position of the first actuator to actuateitsswitch relative to the. stop. Since the switch is. inv fixedposition. on

2,826,650 Patented Mar. 11, 1958 ice thefranre, changing the position ofthe; stop changes the zero position of the rotatable system and hencechanges the position of the actuator relative torthe switch. The

length; of the second timed period is determined by the positions :of:the.- respective actuators. Since the switches are both fixed to theframe and. do not move relative to 'oneanother, adjustment of the secondactuator to actuate its associated switch relative to the position .of.the'first actuator will change the second period timed withouteffecting; the; first. .Theadjustment of the timing periods may beaccomplished within the scope of the present invention by various meansin addition to the preferred means described. In addition to adjustmentof the zero position by movement of the stop-and adjustment of therelative angular positions of the actuator means, it is possible toadjust the timing. of the device of the present invention by changingthe position of the switch means. Variouscombinations of adjustments maybe employed. lmorder to simultaneously vary the two consecutiveperiods-,jtwoadjustments may be made selecting two-of-thefollowing:movement of the stop, movement of either or both of the actuators, ormovement of either or-both of theswitches.

For .a better understanding of the present invention reference to thedrawings: which show a. preferred embodiment; will. be made. Thesedrawings may be described as follows:

Fig. 1 is. a side elevationalwiew of the preferred embodiment 'withqthecase and certain other parts in section or partially in section;

Fig- 2 is a sectional view taken along line 2-4 of :Fig; 1 showingcertain parts partially broken away;

.Fig. 3 is a sectional view taken along line 3-3 of Fig. 1 showingcertain parts partially broken away;

Fig. 4 is a partial front elevational view whereinpart of oneof theknobs is broken away;.

Fig. 5 is. a schematic representation of the stop, the limiting arm,the-two cam actuators and their associated followers; which are in turncoupled to. switches (not shown) .inzero position;

Fig. 6 is a schematic drawing similar to Fig. 5 but showing; theactuatorsadvanced to the point of actuation of the firstzswitch but notthe second; and

Fig. 7 isa schematic drawingsimilar toFigs. 5 and 6 but showing theactuators advanced in position tothe point where both switches have beenactuated.

Referring. now tov the drawings, Fig. 1 gives an' impression. of. theoverall structure of: a preferred embodiment of the present invention.Planar mounting decks 10, 1-1, l2v provide the surfaces on thesupporting frame on which most of the structure of the present inventionis mounted. Casing 13, which is-advantageously rectangular in section,is employed tov enclose much of. the structure tokeep it dust free. Thiscasing inother embodimentsv might. be made of. any desirable crosssection. Column 14 and a similar column on the other side of thestructure separate mounting deck 10 and the planar end of casing 13 andsupport the casing on the mounting frame. Columns similar. to column 14are advantageously employed between each pair of. supporting decks. Somesuchconnections are required between the various portions of the supportframe, of course. Hbwevensince such support members are conventional,for the sake of simplicity and clarity they have been. omitted in thesedrawings.

The drive power of the present invention is-supplied by motor 16 throughgear connections within gear box 17 to drive shaft 18. Pinion 19 isfixed on to drive shaft 18. .Pinion. 19 meshes with. a pair ofoppositely disposed. planetary gears 20 which are supported ondiametrically opposedradial arms 21a and 21b of. three armed crossmember 21. Cross. 21 is supported on the end of axle 22 which liescoaxial with drive shaft 18. The direct support for gears is furnishedby stud shafts 23 on arms 21a and 2112. Gears 20 are rotatably mountedon said stud shafts and held in place thereon in any conventionalmanner. A pair of gears 24 also rotate about studs 23. One is fixed toone gear 20 on its stud so that they rotate in unison. The other gear 24is connected to the other gear 20 through a spring 24', therebyproviding an anti-backlash system for the planetary gearing, and alsonormally rotated in unison with it. Gears 24 in turn mesh with spur gear25 which is free to rotate relative to shaft 18 with which it iscoaxial. unison with said drum. In the preferred arrangementillustrated, gear 25 and drum 26 are both fixed to sleeve 27 which issupported on a bearing (not shown in detail) surrounding a portion ofdrive shaft 18 and Gear 25 is fixed to drum 26 to rotate in secured togear box 17. A slip ring indicated generally at 27 maintains them on thehearing.

The drum 26 has a peripheral cylindrical flange, the inside surface ofwhich is covered with material 29, such as rubber, having goodfrictional properties. Brake shoe 31 having the contour of this insidesurface of the drum is closely spaced to said surface and arranged to bebrought into contact with it. Shoe 31 is supported on a complex arm 32and is provided with a knurled outer surface. Arm 32 is, in turn,rotatably mounted in that it is fixed to bushing member 34. This bushingis tubular and rotatable about a stud shaft 35 which is afiixed toplanar mounting deck 10. Arm 32 is a planar sheet metal member parallelto deck 10 having a right angle bend in it so that, as shown in Fig. l,the arm extends laterally back toward the middle of the shoe where shoe31 is supported. Spring member 33 is rises vertically along one side ofthe structure and then 1 member 33 thus tends to urge mounting member 32downward, actually in a circular path about pin 35. Hence spring 33tends to keep the brake shoe 31 away from drum 26. Shaft 35 alsoprovides a support post for fulcrum member 38 which provides a fulcrumfor lever member 39. One end of lever member 39 lies within an openingin brake shoe supporting member 32. Its other end lies above solenoid40. Upon energization of said solenoid, lever arm 39 pivots aboutfulcrum member 38 driving shoe support member 32 upward and hencedriving shoe 31 into brake 29.

Lever arm 39 has a lateral extension member 41 preferably composed of aninsulator affixed to its remote end adjacent the solenoid 49. Thisextension extends above flexible spring metal arm 42. A contact 44 ismounted on member 42. The resilience of arm 42 tends to urge it upward.Member 42 is supported between a stack of dielectric blocks 43 which, inthis instance, is supported on a remote part of fulcrum member 38. Alsosupported by the same stack of insulators 43 is flexible metallic member45 which is in- I sulated from member 42. This member supports contact46 in a position opposite contact 44. When solenoid 40 is energized andlever arm 39 moves from the position shown, contacts 44 and 46 will beclosed.

Returning again to supporting axle 22 for cross arms i 21, it will beseen that axle 22 and shaft 18 are not connected together but aremachined to fit so that the end of axle 22 provides a bearing for theend of coaxial shaft 18. Axle 22 extends through a mounting deck 13where it is supported in a suitable bushing and in turn ll extendsthrough support deck 12. A cam member 50 is held in place on axle 22 byset screw 51. A second cam member 52 is held in place on a tubularsleeve 53 by set screw 54. Sleeve 53 in this preferred embodimentcoaxially surrounds a reduced diameter portion 55 l of axle 22, its endcontacting a nylon washer 53' located between it and the full diameterportion of axle 22.

asaaeeo p This tubular member 53 is journaled through deck 12 just asthough axle 22 were a single solid piece supporting the two cams.Between cam member 52 and support deck 12, also on tubular member 53, iscam limiting element 56, which is similar to the cam members in itsgeneral shape. Cam limiting element 56 is held on tubular member 53 byset screw 57. A projection 58 from this element is provided to interceptstop 59 on deck 12 of the frame and thus effectively to limit rotationof the sleeve 53 and hence cam 52. Stop 58 is fixed relative to switch56, since both members are supported on the frame. Thus, the immediatepurpose of stop 58 is to prevent rotation of cam 52 past a pointimmediately beyond that at which said switch 65 is actuated.

A switch 61 is provided with a lever arm 62 which is pivotally supportedin a position where its associated 'roller member 63 may serve as afollower of the surswitch 65 is arranged parallel to the first switchwith its lever arm 66 similarly oriented to lever arm 62 and its roller67 in position to follow the surface of cam 52. Reference to Fig. 3 willgive a clearer impression of the manner in which the switch parts coactwith one another. In this case the lever 66 moves against switchactuating plunger 68 of switch 65 in order to close the normally openswitch. In other cases the same movement might be used to open anormally closed switch. Alternatively, the cam surface might be changedto urge the lever 'down most of the time and release it at the desiredtime 'of actuation.

Disc-like member 71 having a knurled edge to facilitate its rotation issecured to sleeve 53 for adjustment to various fixed positions relativethereto. Said disc-like member 71 is permanently aflixed to a segment ofcrown gear 72. A tubular member 73 is provided with a mating crown gearedge 73a. Radial pin 74 penetrates tubular member 73 and lies slidablywithin a slot in member 75 which parallels its axis. Member 75 is heldpermanently within member 76 by means of radially extending pins 77which are engaged within a circumferential groove in member 75. Thiscircumferential groove makes possible relative rotation between members75 and 76. Member 76 has a smaller inner diameter portion than member75, which portion is threaded to engage threaded end portion 78 of axle22. Pin 79 through axle 22 engages slots parallel to said axle andpermits member 75 to he slid axially over it in order to hold members 75and 73 in fixed angular position relative to the axle 22 andspecifically to threaded part 78. Member 76 is left free to rotate,however, and is conveniently provided with a screw driver slot extendingdiametrically across one end so that it may be conveniently advanced onthe threaded end of the axle to force members 75 and 73 axially forwarduntil crown gear 73a and crown gear segment 72 mesh. Their meshingprevents further relative rotation between the members 71 and 73 and theassociated members coupled together against rotation by pins 74 and 79and, hence, prevents relative rotation between sleeve 53 and portion 55of axle 22. Furthermore, crown gears fix the sleeve 53 relative to axle22 and hence fix cams 50 and 52 relative to one another in one of afinite number of discrete positions determined by the number of teeth ingear 73a. To prevent even the slightest relative movement of shaft 22and sleeve 53 when locked together by the above-described ratherintricate assemblage of parts the forward slotted portion of member 75and the mating portion of the rear face of the forward part of member 73are tapered whereby when forced together the pins 74 and 79 are tightlyclamped in the slots of member 75..

' It will be seen from Fig. 2 that the cross-like member .21 has on itsthird arm 21 a shoulder 81 which cooperates with stop '82. This stop issupported-on gear 83. Gear 83 is supported on axle 22'but is not fixedthereto so that .it is free to rotate about axle 22 and its common axisof rotation. Since shoulder '81 is on arm 210, which has the same axisof rotation as the gear, .any position of the gear will leave stop 82 inthe path of rotation of said shoulders. As may be seen in'Fig. 1, aspring 84 in the form of a helix is supported on axle 22. One end ofspring 84 is fixed to the deck 11 and the other end of said spring isfixed to cross 21. Accordingly cross 21 tends to rotate in the directionopposite that produced by the motor drive, as will hereafter beexplained. This rotation and spring pressure urges shoulder 81 againststop 82 as appears in Fig. '2 so that arm 21c and shoulder 81 provide alimiting arm to limit rotation of the rotatable system.

Gear 83 meshes with gear v85 which isrotatably mounted on a stud 86,supported on mounting deck 11. Gear 85, in turn, meshes with .gear 87which is fixed .to rotatable shaft 88 which extends through. mountingdeck .11, and into a bearing in mounting deck 12. Gear89 is fixed toshaft 88 adjacent to mounting deck 12-. It may .be held in place by aset screw or other appropriate means penetrating its hub and shaft 88.Gear ,89 meshes with gear 90 which is supported on rotatable shaft 91which penetrates mounting deck 12' through bushing92. Shaft 91 isterminated in knob '93 which is held in place on shaft 91 by set screw94 which terminates .at a flat surface of shaft 91 or by otherappropriate means. The

.knob isalsopartially hollow and is provid'edxwith spring means 97suppor-tedby an adjustable position tab 98 mounted on deck 12. Spring97"is' preferably provided with a. roller member 99 which engages aserrated or scalloped inner cylindrical surface: within the knob. Alsowithin the knob is a, shoulder 101 supported on a flange .102 which isrotatably adjustable about the axis of rotatron of knob 93. Shoulder1-01 is arranged to abut stop 1-03'on knob 93. The beveled surface 95 ofthe knob .93 is advantageously calibrated in order to be read against amark on the exposed surface of the mounting .deck 12. i

A planar support. 1.06 arranged at right angles to decks 1'0 and 11between which it extends is provided with mounting flanges 106a and10612. Flange 106k and part of support 106 are cut away in Fig. 1.Support 106, in turn, supports a mounting flange 107 having a portionfixed flat against support 106 and a portion perpendicular to support106 and decks and 11. A solenoid 108 may he supported at one end on theportion of flange 107 parallel to support 106. Mounted on the bottom offlange 107 is a stack of insulators 109 which separate aridhold in placeapair of conductors 110 and 111 from which extend flexible arms 110a and111a. These arms 110a and 111a, in turn, support contacts 112 and 113;Flange 107 also supports a thin highly flexible member 115which,rin-turn,.supports solenoid armature 116. The armature. is anL-shaped member the base of which is fixed to flexible member 115sufiiciently far from the end of flange 107 to permit the armature 116to move toward'and into contact with the core of solenoid 108 A leverarm 118 is fixed to the armature and is provided at its remote'end withan insulator post' 119 which is so arranged that, upon movement ofarmature 116, arm 118 forces post 119 against flexible arm 110a in sucha way as to close contacts 112 and 113. A stop 120' isfixed on flange107 above the end of arm 118 to limit its upward travel when armature116 is released.

Figs. 5-7 show schematically the operation of the embodiment describedand represent various stages in the consecutive timed periods. In these'figure's, despite schematic representation, thesarne numbers are usedto designate the parts as are used in Figs. 1-4. These drawings will be,used to describe the operation of the device of the present inventionhereafter.

Referring again to Fig. l, in actual operation of the device, the motordrives shaft 18 causing rotation of pinion 1'9, Pinion '19 causesrotation of gears '20 which are meshed with .it. Rotation of gears 20necessitates rotation of gears 24 which are respectively fixed to gears'20. Gears '24 in turn mesh with gear 25. The driving of gear 25 causesrotation of drum 26. No movement is imparted to axle 22. At av signal,which causes solenoid 40 to be energized, lever arm 39 is attracted tothe solenoid and hence urges shoe 31 up. When shoe .31 contacts theinside surface 29 of drum 26, the high frictional properties of saidsurface will prevent further rotation of drum 26. Since drum 26 will notrotate, rotation of gear 25" is impossible. Consequently, the drive ofpinion 19 'will cause gears 24 to revolve about gear 25, thus movingcrossdike member 21 in a rotational movement in opposition to-thedirection. of rotation urged by spring .84.

Theprocess of actuation of each of the switches may be envisioned. byreference to Fig. 3. Here it will 'be seen. that cam 52 as it rotateswill eventually have a discontinuity in the form of a shoulder betweenlarger and smaller diameters. Roller 67 on lever arm 66 will roll up,this shoulder and lever arm 66 will be depressed accordingly. As leverarm 66 is depressed, actuating button 68 of. the. switch will also bedepressed into opening or closing a circuit as desired. Actuation of theother switch advantageously occurs in the same way.

Rotation of cross arm 21,- of course, produces rotation of shaft2'2.Shaft 22 may be visualized as carrying ilirnitingarrn 21c and actuatormember 50 and 52 on a single rigid, axle as shown. in Figs. 57.. Theinitial or zero, positionv shown inFig. $.(also shown in Figs. .1-3) isthat one intowhich the axle 22 is urged under the pressure of spring 84.This position is maintained because of the spring pressure until shaft22 begins to rotate. Thereafter, switch 61 will be actuated when cam 50is rotated to the point of discontinuity at which point the cam follower63 will be depressed as may be .seenin Fig. 6. Actuation of switch 61marks the end of the firsttimed period. Itv also marks the beginning ofthe second timed period. Rotation of axle 22 i continuous, of course.Finally cam 52 depresses follower 67 and actuates switch 65. This marksthe endof the second period.

The type of elements employedin the practice of the present invention isnot limited to those described. For example, it is possible tosubstitute other types of actuators for the cams. One possiblesubstitution might be the use of rotatable actuator arms which cooperatewith toggle type switches. Other such substitutions of the partsdescribed in accordance with their particularfunction are intended to bewithin the scope of the present invention.

Although the purpose of the structure of the present invention is totime consecutive periods, the particular feature which distinguishes thepresent invention is the ability to adjust the length of at least one ofthe periods timed and preferably to independently adjust the length ofboth periods. In the preferred embodiment of the present invention bothperiods are adjustable but adjustment is so arranged that one period iseasily fixed and readily adjustable whereas the other is designed tobeset and retained in position for a long period of time, perhapsinvolving many resettings of the readily adjustable timing period.

In the preferred embodiment, setting the-secondperiod, which is the onewhich is relatively fixed, is accomplished by relative movement betweenknob 73 and dial 71. Member 76 isprovided with a screw driver slotdiametrically arranged across its end. A screw driver may be inserted inthe slot and member 76 turned to remove it from threaded portion 78ofaxle 22; The withdrawal of member 76 also causes .75 which-ismechanically coupled to member 76 through .pins77 as previouslydescribed. Pins 74 prevent rotacam 52 may be rotated relative to axleaxial withdrawal of member tion of member 75, but the arrangement of theslots conbe disengaged from the section of crown gear 74 on disk 71.Thus loosened, the tubular sleeve 53 supporting portion 55 by rotationof disk 71. Changing the position of cam 52 with respect to cam 50adjusts the time interval between the actuation of switches 61 and 65.It should be noted,

however, that as sleeve 53 is rotated-changing the position of cam 52relative to cam 50, it maintains the projection 58 on member 56 in thesame position relative to :cam 52 so that rotation past the portion ofincreased di- *ameter on cam 52 is rendered impossible. 'The disk 71 andmember 73 may be calibrated with respect to their angular positionrelative to one another, using a dial 125 mounted on member 71 and asuitable mark on member 73 to be compared with dial 125. The number ofdiscrete settings is determined, as previously mentioned, by the numberof teeth in the crown gear 73a. In one preferred timer, thirty secondsis the maximum length of the second period.

Adjustment of the relative positions of the cams 50 and 52 by adjustmentof cam 52 will not afiect the length of the initial timed period sincethe limiting arm and cam 50 are fixed relative to axle 22 and cannot bemoved. In order to change the first timed period, the'position of thestop 82 relative to the frame is modified. It should be noted that justas it is not possible to change the first period by the cam adjustmentdescribed, it is not possible to change the second period by themovement of stop 82. Since stop 82 determines the zero position of theaxle 22, changing the position of the stop will have the effect ofchanging the starting position of axle 22 and hence of cam 50 relativeto its switch so as to lengthen or shorten the period prior to theactuation of switch 61 by said cam. The adjustment of stop member 82 issimply accomplished by the rotation of knob 93. This knob is placed inan accessible place for ease in operation and is preferably placedadjacent the knob adjustment of the second period for ease incomparison. Knob 93 causes rotation of shaft 91 and hence gear 90. Gear90 drives shaft 88 through gear 89 and gear 87 on shaft 88 drives gear85. Gear 85, in turn, produces rotation of gear 83 'on which stop 82 ismounted. Thus, stop 82 may be positioned at a variety of angularpositions relative to axle 22 and the cams 50 and 52 by rotation of knob93. In whatever position stop 82 is finally set, tab 81 on thepositioning arm 21c of cross 21 will be driven against it. Since thepositioning arm 21c is mounted on axle 22, it will determine theposition of said axle.

Knob 93 will tend to remain in its set position because of theinteraction of roller 99, which is spring connected to the frame aspreviously described, and the scalloped inside surface 100 of the knob93. The roller will, of course, seek the bottom of the various scallopsand, hence, each scallop defines a discrete position of the knob withrespect to the frame. Since each discrete knob position defines a stopposition relative to the frame, it is possible to calibrate knobpositions relative to the frame to show the time which will elapsebetween the time the limiting arm leaves the stop and the time when thefirst cam to do so actuates its associated switch. The preferred way ofdoing this is to put a single indicator mark 127 on the frame and ascale indicating time in seconds and fractions thereof on large diameterflange 128 of the knob. In pracfice it is common to put the indicatormark 127 on a member 129 which permits its slight angular adjustmentrelative to the frame in order to make initial calibration easier andtofacilitate recalibration of the de- 'vice, if necessary. The supporttab 98 for spring 97 holding. roller 99is advantageously made adjustablein order to permit variation in the spring tension and hence the forceneeded to turn the dial. Shoulder 161 which cooperates with stop 103 isalso advantageously provided .with a support tab the position of whichrelative to the frame may be angularlyadjusted about shaft 91 as anclose a circuit to start an operation which is to be timed.

Since the contacts are closed by the same fast action lever arm 39 whichurges the brake shoe 31 into position, this arrangement is excellent forsynchronizing eifects. The contacts 112 and 113, ,on the other hand,instead of being actuated by the mechanical action which has to do withinitiating the timing period, may provide a high current switch which isclosed iii response to actuation of solenoid 108 through the leversystem previously described. The solenoidmay be energized by the closingof a low current switch, such as switch 61. Although such switchfunctions are contemplated, the associated wiring necessary to theirfunctioning has not been shown or described because the wiring will beconventional. For this same reason, wiring has been omitted from themotor, solenoid .and'switch "elements. Wiring in a practical structureof the present invention is a matter of choice consistent with goodmechanical design of the structure. The general electriclcircuitarrangement as described and relative mechanical positioning of thecomponents are of particular advantage, however. I 7 An example of oneapplication of the present invention is its'use as an actuation devicefor aerial movie cameras which are intended to record bomb hits. The.timer in such an application might be arranged so that closing ofcontacts 44 and 46 would release bombs. The first'timedperiod would thenbe the time required for the'bombs to reach the ground. At the end ofthis first period actuation of switch 61 would cause the contacts 112and 113 to close in a circuit which would begin operation of the camera;The second period would be the required picture taking time; At the endof the second period, actuation of switch 65 would stop operation of thecamera. The time of camera use would not need to be adjustedfor each runon the target. The time for the bombs to fall from the bomber to thetarget, however, might vary considerably. The preferred embodiment ofthe invention has the advantage that this first period is able to beeasily-adjusted to the time calculated to elapse between the release ofthe bombs and their striking the target. The period of camera operationis not easily adjusted, however, so that an inadvertent change in it oran error in setting the wrong dial is unlikely. This period is set onthe ground by a technician before the plane leaves on its mission.

Although for most applications the preferred embodiment will be'muchpreferred, it is possible to modify the structure as described quiteradically within the scope of the present invention. For example,instead of moving cam 52 with respect to cam 50, it is possible bymoving-the switch 65 about the axis of rotation to change the timingperiod in the same way. Also, although it is not generally desirable tomove the actuator, corresponding to cam 50, which marks the end of thefirst period and thev beginning of the second, there may be instanceswhere its movement would be desirable to maintain the total lengthof thetwo periods constant while changing the lengths of the. individualperiods. This could as well be done by movingthe switch 61 at a fixedradius about the axis of rotation of actuator 50. In addition all sortsof combinations of adjustments are possible in order to obtain dilferenteffects. p

Many modifications of this preferred embodiment will occurto thoseskilled, in theart and many structures withable pulse length and anadjustable cyclingp'eriod.

We'claim:

l. "A motor driven switch'timing device comprising a frameya constantspeed motor drive on "said "frame, "a rotatableasysterrr supported onthei frameehaving its parts coupled togethen-for simultaneous rotation,said system containing first and second timing actuators and alimitfingarm, means couplingtherotatable: system to'the drive inresponse to a signal, resilient means urgingthe retatable systemtorotate in the "directionioppos'itei thatimp'osedi-bya positiontointercept the 'limitingarrn rand consequently =lirniting 'the rotationimposed "byisai d resilient means, fir'standzsec'ond'switches-supportedorf'the frame in 'posithe drive; stopmeanssupported on the 'frame in tion to be actuated by said first andsecond actuators, respectively, in the course of rotation of the systemaway from the position in which the limiting arm engages the stop, andmeans for independently adjusting said first and second timing actuatorsrelative to their respective switches whereby sequential andindependently adjustable time periods may be obtained.

2. A structure as described in claim 1 wherein the stop means is mountedon a member the position of which may be changed by rotating it relativeto the frame about the same axis of rotation as the limiting arm, one ofthe actuators is fixed relative to the limiting arm and the otheractuator angularly adjustable relative to the fixed actuator.

3. A motor driven switch timing device comprising a frame, a constantspeed motor drive on said frame, a rotatable system supported on theframe and containing first and second timing actuators on a common'axleand a limiting arm coupled to the axle for simultaneous rotation, meanscoupling the rotatable system to the drive in response to a signal,resilient means urging the rotatable system to rotate in the directionopposite that imposed by the drive, stop means supported on the frame ina position to intercept the limiting arm and consequently limiting therotation imposed by said resilient means, first and second switchessupported on the frame in position to be actuated by the first andsecond actuators, respectively, in the course of rotation of the systemaway from the position in which the limiting arm engages the stop, andmeans for independently adjusting said first and second timing actuatorsrelative to their respec tive switches whereby sequential andindependently adjustable time periods may be obtained.

4. A timing device in accordance with claim 3 wherein the stop ismounted on a gear which is rotatable about the same axis of rotation asthe limiting arm and which is in turn coupled to a dial remote from saidgear, the positions of said dial relative to the frame being calibratedto indicate the corresponding positions of the stop relative to theframe.

5. A timing device in accordance with claim 3 wherein part of the axleconsists ofcoaxial pieces, one of said actuators being supported on theouter tubular piece of the axle and the other of said actuators beingsupported at a position axially removed from said one actuator on theinner piece of the axle, and means at one end of the axle for rigidlyfixing together the two pieces.

6. A timing device in accordance with claim 3 wherein the actuators maybe angularly adjusted relative to one another, one of said actuatorsbeing supported on a portion of the axle which consists of a tubularmember surrounding the main axle shaft and the other being sup-'fresilienfmeans, framejcam' 1 foliowers coupling the switches to the'actua- ,portedon saidmain axle shaft, meansv at one end ,of thejaxlefor 'i'igidlyfixing" together the two portions, the" end'ofthetubular member-"bearing a dial, andthe end of "the main axle'shaftibearing a knob,;said knob. and dial 'beingJc'aIibrated to fshowthe relative positions of the actuators they supporn'and' means forreleasably *holding 'th'eknobxand'the dialiinfixed position relative toone "another.

7. A-"motor driven switch'timing device comprising a framegaconstantspeed motor drive'on saidframe, a'ro- 't'atablesystern supportedonithef'frame coupl'edtogether -for3simdltaneous rotation, said systemcontaining first "arid second camme'rnbcrs constituting timingactuators, a

common axle. and a limiting arm coupled to the axlefor simultaneous'rota'ti'on,;means coupling the rotatable syste'm tothe"diive=-in"responseto a'isignal, resilient means urging. therotatable .system to rotate'in the direction opt'po site" that ir'nposedby the drive, stop means supported "oni'the frame in 'afposi'ti'on to;'intercept -thelimiti-ng arm anfd consequently' limiting the rotationimposed by said firstand'isecond switches mounted onthe"tors,"and"means"for independently adjusting said first and secondtiming actuators relative to their respective switches wherebysequential and independently adjustable time periods may be obtained.

8. A timing device as described in claim 7 wherein the stop is supportedon a member rotatable relative to the frame having its axis of rotationon the axis of rotation of the limiting arm, and wherein the axle iscomposed of a main shaft on which one of the cam actuators is fixed anda tubular member coaxial with said axle on which the other of said camactuators is fixed, the tubular member being terminated at the end ofthe axle in a dial and the axle being terminated at its end in a knob,and means for releasably holding the knob and the dial in fixed positionrelative to one another to prevent relative rotation of the cams.

9. A timing device in accordance with claim 7 wherein the stop ismounted on a gear rotatable about the axis of rotation of the limitingarm, said gear being in turn coupled to a knob for remote rotation ofsaid stop, and wherein the axle is composed of a main shaft on which oneof the cam actuators is fixed and a tubular member coaxial with saidshaft on which the other of said cam actuators is fixed, the tubularmember being terminated at the end of the axle in a dial and the rodbeing terminated at said end of the axle in a knob, and means forreleasably holding the knob and the dial in fixed position relative toone another to prevent relative rotation of the cams.

10. A timing device according to claim 8 in which the means forreleasably holding the knob and the dial in fixed position relative toone another comprises crown gears mounted respectively on said dial andsaid knob and adapted to mesh with each other when said knob and saiddial are moved toward each other, and means for mounting said knob onsaid axle for adjustment longitudinally thereof, said last-mentionedmeans including a threaded collar adapted to be threadably supported onthe end of said axle for movment relative to the knob to urge said knobtoward said dial.

11. A timing device according to claim 10 in which a tapered membersurrounds the end of said shaft be tween said collar and said knob, saidtapered member being provided with slots in its tapered portion toreceive a pin extending through said axle and a pin extending through aportion of said knob and said knob having an oppositely tapered openingto receive said tapered portion of said tapered member whereby when saidtapered member and said knob are urged together the pins are firmlyclamped in said slots.

12. A timing device as described in claim 1 wherein the constant speedmotor drive includes a planetary drive gearing system comprising adriving gear adapted to be tric with said driving gear, two pairs ofplanetary gears rotatably mounted on studs'fixedly supported by saiddriven shaft, one of each pair of planetary gears meshing with saidbrakable gear and the other of each pair of planetary gears meshing withsaid driving gear, and spring means connecting the planetary gears ofone pair to each other to permit relative rotation thereof against theresilient force exerted by said spring means, whereby backlash in theplanetary drive gearing system is diminished.

13. A timing device according to claim 12 in which the planetary gearsof one part are fixedly secured together against relative rotation.

14. In a motor driven switch timing device, a planetary drive gearingsystem comprising a driving gear adapted to be fiexedly supported by themotor drive shaft, :1 brakable gear member mounted for free rotationconcentrically with respect to said driving gear, a driven shaftconcentric with said driving gear, two pairs of r 12 planetary gearsrotatably mounted on studs fixedly supported by said driven shaft, oneof each pair of planetary gears meshing with said brakable gear and theother of each pair of planetary gears meshing with said driving gear,and spring means connecting the planetary gears of one pair to eachother to permit relative rotation thereof against the resilient forceexerted by said spring means, whereby backlash in the planetary drivegearing system is diminished.

15. A planetary drive gearing system according to claim 14 in which theplanetary gears of one pair are fixedly secured together againstrelative rotation.

References Cited in the file of this patent UNITED STATES PATENTS1,763,023 Tyler June 10, 1930 2,102,131 Schmid Dec. 14, 1937 2,312,077Cowles Feb. 23, 1943 2,388,686 Habig Nov. 13, 1945 2,444,146 SchellensJune 29, 1948 2,465,201 Coombes Mar. 22, 1949 2,506,784 Haydon May 9,1950

